The CXG Sphinx Legend chess program was created by the Hungarian programmer Guyla Horvath and is based on his “Pandix” program that won the amateur world championship in 1987.
The normal out of the box playing style is a little passive but you do have the ability to change its play in 9 styles ranging from ultra-cautious play when the program is WHITE and ultra-aggressive play when it is BLACK (style number 1), to ultra-aggressive play when the program is WHITE and ultra-cautious play when it is BLACK (style number 9). The normal style is style number 5.
The CXG Sphinx Legend also has some other interesting features:
After the computer has made a move you can ask it the question: “Why did you not play ......?” and suggest a different move. The computer will then tell you what it expected you to play in reply if it had chosen your suggested move. (This will not always be the best move but it will be a move which the computer considered strong enough to counteract your suggested move.)
USER PROGRAMMABLE EVALUATION FUNCTION
Every chess program needs to know how to evaluate a chess position. It does so using an “Evaluation Function” which gives a point-score to various features of the position, such as king attack, material, mobility, center control, etc. Associated with each of these features is a “weighting” which tells the program how much importance to attach to a feature.
The CXG Sphinx Legend allows you to change these weightings so that you, the user, are programming the computer to play in a particular way. For each feature the minimum weighting is 0 (when this feature would be completely ignored) and the maximum weighting is 99 (when the feature will be given 10 times its normal importance).
The normal factory out of the box weighting is 50 for all of these features. There are 7 features in total where the weightings can be adjusted from 0 to 99:
- Pin against the enemy Queen.
- Pawn structure around the King.
- King attack by pieces.
- Aggressive play by White’s pieces.
- Aggessive play by Black’s pieces.
- Doubled pawns.
- Rooks on open and half open files.
Partial excerpts taken out of the CXG Legend User Manual.